Glass threads can provide insight into Mauna Loa eruption

Abstract

On Nov. 27, the Hawaiian volcano Mauna Loa reawakened , spewing lava from its summit for the first time in 38 years. During its eruption , it also expelled amber-colored strands of volcanic glass known as Pele’s hair, thin filaments that form when lava splatters and gets stretched by the wind—“sort of like a taffy pull,” explains Aaron Pietruszka, a geochemist at the University of Hawaii at Manoa. These glass threads serve as an invaluable tool for geochemists seeking to understand the recent eruption. According to Kendra Lynn, a volcanologist at the Hawaiian Volcano Observatory, scientists can measure the amount of calcium and magnesium in the hairs to calculate the lava’s temperature, which can indicate whether hot, fresh magma is feeding the system. “Hotter erupting lava flows farther faster, which you can imagine matters a lot [when] thinking about hazards,” Lynn says. Because the hairs are formed by rapidly cooled